Methods are employed for the extraction and purification of antigonadotropic substance from bovine pineal glands which is believed to be a peptide of MW 500-1000. The material is localized and characterized by gel filtration, ultrafiltration, ion exchange chromatography, thin layer chromatography, electrophoresis, preparative paper chromatography, high pressure liquid chromatography and quantitative amino acid analysis. A determination of the sequence (structure) of the compound will be undertaken and synthesis will be carried out. Studies on the effects of the purified antigonadotropin, and when available synthetic analogs on the development of puberty in immature animals and inhibition of ovulation in adult female rats will be continued.